Fehmi Keçe

Predicting Early Reconnection with Procedural and Biophysical Parameters 153 7 and ostium of the PVs) is thought to occur immediately after ablation, the time-frame of this development is not yet clarified (13). Nonetheless, it seems reasonable to perform a single effective freeze instead of an ineffective freeze followed by a second application to treat dormant conduction. 7.4.3 Biophysical and procedural parameters In a prior study, a time-to-isolation ≤65 seconds and a longer-time-cycle integration (which is the integration of time-to-isolation and the number of freeze-cycles) ) were associated with the absence of acute PV reconnection after a single freeze of 180 seconds and a waiting period of 30-minutes without adenosine testing (14). In another study, a time- to-isolation ≤60 seconds and a thawing time at °0 C of ≥10 seconds were associated with durable PV isolation in patients undergoing a repeat ablation 14±3 months after the index cryo-ablation procedure (7). Biophysical parameters as a predictor of early reconnection have been previously analysed. In this study isolation durability was tested without adenosine after a waiting period of 30 minutes. Only the temperature slope (which was strongly correlated with nadir temperature) predicted acute isolation (15). The authors suggested that this information might be useful to decide for an pull-down manoeuvre or aborting a cryoablation. Our results extend the results of these studies as we found that the number of unsuccessful freeze attempts, the nadir balloon temperature and time-to- isolation were the most important predictors of ERC with incorporation of a waiting period of 30-minutes and adenosine testing. 7.4.4 Clinical Implications This study identified three parameters that can predict the absence of ERC and may be helpful to avoid a waiting period of 30 minutes and adenosine testing in selected patients. Implementing these parameters can shorten the total procedure time. By avoiding a 30 min waiting period, it may, in addition, also decrease the occurrence of oedema that might influence additional application success. Based on the cut-off values of the three parameters we constructed a table for clinical decision making which can be easily applied during the procedure to decide for 30min of waiting with adenosine testing. In prior studies, single parameter cut-off values have been defined for time-to-isolation and nadir balloon temperature (16). As three different parameters predicted ERC in our study we suggested a multivariable prediction model, which was stronger than a single parameter prediction model in our data. In the new version of the cryoconsole, biophysical data will be directly available, which facilitates peri-procedural decision-making. Larger studies, preferably with adenosine testing to reveal dormant reconnection sites, should be performed to develop